F flierfox Member Joined Mar 28, 2020 Posts 7 Mar 28, 2020 #1 Hello, I've been trying to upgrade my SOs Win10 Pro 1703 to the W10 1909 version using all methods, including the today downloaded MediaCreationTool. It failed and rolled back with the following error: "0x8007001F - 0x20006 The installation was not successful. Error in Phase SAFE_OS during REPLICATE_OC." I've spend the day on google and from their recommendations this is what I did: I deleted unnecessary software, there is no virus scanner on the system any more (besides MS Defender), I removed all old USB devices, I've run a disc clean up (using the windows tool) on C:\, I tried running the upgrade from USB,DVD and from the hard drive. Nothing helped. Now I came here because I saw you could help people out with this problem where others just gave up at some point and made a fresh install. Please help me...you're my last hope.